Methane is, yes. You turn it into a bit of CO2 which is magnitudes less potent. Methane would likely not be sustainable for long, it's mainly a result of processes that humanity is likely to ultimately phase out at one point or another in the future, we get it from stuff like rotting garbage and crude oil processing. Solar is not a "pipe dream", it's quite possibly the ultimate energy form humans will harness on earth. No one can promise fusion reactors will ever work, even in a million years. There are lots of stepping stones along the way though. Methane could be a good one.